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Technical note: effectiveness of different methods of continuous marker administration for estimating fecal output
S D Brandyberry1, R C Cochran, E S Vanzant
1Dept. of Anim. Sci. and Ind., Kansas State University, Manhattan 66506.
Journal of Animal Science
|November 1, 1991
Summary
Continuous-infusion pumps effectively measure fecal output in limit-fed steers. Controlled-release chromium oxide (Cr2O3) boluses overestimated fecal output, indicating potential inaccuracies in this method for predicting animal feed intake.
Area of Science:
- Animal Nutrition and Metabolism
- Ruminant Physiology
- Digestive Physiology
Background:
- Accurate fecal output prediction is crucial for understanding nutrient utilization in livestock.
- External markers are commonly used to estimate fecal output, but their administration methods can influence accuracy.
- Limit-feeding strategies require precise monitoring of digestive processes, including fecal excretion.
Purpose of the Study:
- To evaluate the efficacy of continuous-infusion pumps versus controlled-release boluses for administering external markers.
- To assess the accuracy of different marker administration methods in predicting fecal output in steers.
- To investigate potential diurnal variations in fecal marker concentrations and their impact on output estimation.
Main Methods:
- Six ruminally fistulated steers were used in a randomized complete block design.
- Continuous intraruminal infusion of Cobalt-EDTA (Co-EDTA) and Ytterbium chloride (YbCl3) was administered.
- A controlled-release chromium oxide (Cr2O3) bolus was inserted into the rumen of each steer.
- Fecal grab samples were collected at various intervals, and total fecal output was measured over 7 days.
- Marker concentrations were analyzed to calculate fecal output estimates.
Main Results:
- Continuous-infusion pumps effectively administered markers for fecal output estimation in limit-fed steers.
- The controlled-release Cr2O3 bolus significantly overestimated fecal output when using manufacturer-suggested release rates.
- Fecal marker concentrations exhibited minimal diurnal variation, and marker equilibration occurred around 100-120 hours.
Conclusions:
- Continuous-infusion pumps are a reliable method for administering external markers to estimate fecal output in limit-fed steers.
- Cr2O3 controlled-release boluses, under the tested conditions, may lead to overestimation of fecal output.
- The findings support the use of continuous infusion for accurate fecal output measurements in nutritional studies with limit-fed ruminants.